The general procedure for the synthesis of 2-(2-hydroxyethoxy)ethyl 4-methylbenzenesulfonate and diethylene glycol bis(p-toluenesulfonate) from p-toluenesulfonyl chloride and diethylene glycol was as follows: diethylene glycol (1.25 g, 11.8 mmol) was dissolved in water (3.5 mL), followed by addition of sodium hydroxide (0.768 g, 19.2 mmol). The mixture was stirred at room temperature until a clarified solution was formed. The mixture was cooled to 0 °C and a solution of tetrahydrofuran (30 mL) with 4-toluenesulfonyl chloride (2.27 g, 11.9 mmol) was added slowly and dropwise over 20 minutes. After the dropwise addition was completed, the reaction mixture was continued to be stirred at 0 °C for 1 hour. After completion of the reaction, the reaction mixture was diluted with ethyl acetate (150 mL) and water (40 mL). The organic phase was separated, dried over anhydrous sodium sulfate, filtered and the solvent evaporated under reduced pressure. The residue was purified by a dichloromethane/methanol gradient (100/0 → 100/0) using a Biotage Isolera One purification system on an HP-Sil SNAP column to afford the more polar diethylene glycol bis(p-toluenesulfonate) as a colorless oil (1.47 g, 47% yield). The less polar bis-toluenesulfonyl derivative was discarded.1H-NMR (400 MHz, CDCl3) δ= 7.80 (d, 2H), 7.35 (d, 2H), 4.22-4.18 (m, 2H), 3.72-3.66 (m, 4H), 3.55-3.51 (m, 2H), 2.45 (s, 3H).
